1. Field of the Invention
The present invention relates generally to air-conditioning systems and, more particularly, to a coil housing wherein multiple drain pans such as primary and overflow drain pans are built into a segmented pan, which avoids the need to individually build and plumb the auxiliary drain pan or other drain pans.
2. Description of the Prior Art
Generally, refrigeration systems employ an evaporator coil, condenser, fluid control device, compressor, and motor-driven fan, which carries air across evaporator coils. The most common type of air conditioning system is the “split” system, also called a “central” air conditioning system where the condenser is located outside and the evaporator is located inside.
In the split system, the condenser cools the refrigerant using the ambient air outside of the home (or other conditioned space). That refrigerant is then carried into the home where it passes through the evaporator coils. Inside the air handling unit (AHU), a motor-driven fan passes air from within the conditioned space over the coils, transferring heat from the inside air to the coils thereby cooling the conditioned space. This system is favored in humid climates for its ability to dehumidify the conditioned space. During the refrigeration cycle, moisture condenses on the evaporator coils and drips off within the AHU. This condensation is typically recovered by a drain pan and disposed of via a drain line to the outside or a plumbing system.
Drain lines can become occluded by mold or other microbial growth, rust, or debris, resulting in overflow of the drain pan. AHUs are often installed in residential attics, where overflows can result in considerable damage to a home's interior. A number of methods have been developed to prevent such damage.
For example, use of an overflow drain pan for various components of heating and cooling systems is well known. It has long been the practice of installers to fashion a suitable system of drain pans when installing a coil. This practice requires significant additional time and cost over the cost of the coil.
One installation method includes a secondary drain line installed slightly higher on the drain pan than the primary drain line to act as a backup in case the primary becomes occluded. Examples employing this method include, U.S. Pat. No. 5,715,697 to Rust et al., U.S. Pat. No. 5,904,053 to Polk et al., Pub. No. 20050109055 by Goetzinger et al., and U.S. Pat. No. 5,987,909 to Martin, Sr.
U.S. Pat. No. 5,715,697, issued to Rust et al. on Feb. 10, 1998, entitled “Condensate Pan with Minimal Residual Condensate,” discloses a condensate pan adapted for use in either a left or right horizontal fan coil installation, including left and right mirror image sides interconnected with a central section having on its lower surface a riser near one end, and each of the halves having a drainage opening on the other end, such that when the evaporator coil is placed in the condensate pan, the pan is tipped about the riser to lower one side and raise the other, depending on whether its a left or right horizontal installation, such that drainage occurs from the lower side drainage opening. The drainage opening is so located with respect to the floor of the pan that, when a drainpipe is threadably connected thereto, its lower inner surface is disposed vertically below the pan floor.
U.S. Pat. No. 5,904,053, issued to Polk et al. on May 18, 1999, entitled “Drainage Management System for Refrigeration Coil,” discloses a refrigeration system including an evaporator coil with a drain pan having alternative drain openings which receive movable primary and secondary drain plugs. A drain pan for use with horizontal A-coils is provided with alternative drain pan openings permitting a variety of configurations whereby the evaporator coil may be oriented in the space conditioning system depending upon on-site conditions. A combination horizontal coil support and drainage duct with coil baffle provides a channel for communication of drainage fluid from the coil to the drain pan.
U.S. Publication No. 2005/010,9055, published May 26, 2005 discloses a drain pan for capturing condensate from a cooling coil in an air conditioning system. The pan includes troughs for collecting condensate and for channeling the condensate to the front part of the pan where the drain openings are located. A back trough has a central hump to enhance the flow of condensate from the back trough in both directions into opposed side troughs. The side troughs are sloped from back to front to conduct the condensate into a front trough to facilitate drainage from the pan. The lowermost portion of the front trough region is defined by a relatively narrow, non-flat area to reduce the amount of condensate residue in the pan.
U.S. Pat. No. 5,987,909, issued to Martin, Sr. on Nov. 23, 1999, entitled “Air Conditioner Drain Pan,” discloses a multi-pan for an air conditioning system which has a coil positionable in one of three orientations, the multi-pan includes, in certain aspects, a bottom pan having walls defining an inner space the bottom pan disposed for receiving water from the coil when the coil is positioned above the bottom pan, a first side pan connected at one end to the bottom pan, the first side pan disposed for receiving water from the coil when the coil is positioned above the first side pan, and a second side pan connected at one end to the bottom pan and spaced apart from the first side pan by the bottom pan, the second side pan disposed for receiving water from the coil when the coil is positioned above the second side pan the bottom pan can be for an A (or V) coil with an air flow space therethrough, or for an M-coil with two air flow spaces therethrough and a middle pan part.
While this method consists of three individual drain pans, only one is utilized in any single orientation of the coils. Therefore, no redundancy is achieved.
Any of these methods, however, cannot address additional problems where drain pans can rust or overflow if the evaporator is being thawed after a recent system freeze. In response to these problems, installers have employed a second, auxiliary drain pans outside, and beneath, the AHUs to catch overflow from the primary drain pan. An example of this method includes, U.S. Pat. No. 6,895,770 to Kaminski.
U.S. Pat. No. 6,895,770, issued to Kaminski on May 24, 2005, entitled “Condensate Secondary Pan for a Central Air Conditioner System,” discloses a secondary condensate pan for a central air conditioning system whereby overflow protection of the primary condensate removal system for a fan coil unit of a central air conditioning system is realized. The secondary pan is positioned directly beneath the primary pan of the central air conditioning system to convey condensate safely outside an enclosure should the primary pan overflow due to clogging of the primary drain line, or leak due to cracks or fissures formed in the primary pan. The condensate secondary pan has a predetermined girth sufficient to extend laterally beyond the primary pan of a conventional fan coil unit. The condensate secondary pan also has a bottom panel which is frustoconical in shape, thus minimizing the pooling of condensate on its surface as well as an integral drain pipe connecting means, thereby eliminating the need for a superfluous user supplied connecting means which is typically made of metal and thus is susceptible to corrosion.
While more redundant, this cited method requires the additional cost and time associated with, purchasing, storage, transporting, installation, and plumbing the additional components. Additionally, the external auxiliary drain pans must be leveled and plumbed separately or they could also overflow.
The same principles described above apply in a heat pump system like the one disclosed in U.S. Pat. No. 6,519,966. U.S. Pat. No. 6,519,966, issued to Martin, Sr., entitled “Air conditioning and Heat Pump System,” discloses an air treatment system having an outer heat exchange coil, an inner heat exchange coil spaced-apart from and encompassed by the outer heat exchange coil, seal structure positioned with respect to both coils so that air pulled through the air treatment system by air movement apparatus may flow through the inner heat exchange coil without flowing through the outer heat exchange coil; and in one aspect, an air treatment system having an outer heat exchange coil; an inner heat exchange coil within the outer heat exchange coil; the inner coil spaced-apart from the outer heat exchange coil; the inner heat exchange coil and the outer heat exchange coil defining an inner chamber therebetween; the inner chamber positioned so that air exhaust apparatus above the inner heat exchange coil moves air into the inner chamber for exhausting therefrom by the air exhaust apparatus; air flowing from outside the outer heat exchange coil, through the outer heat exchange coil, and into the inner chamber; and air flowing from outside the housing between spaced-apart ends of the inner heat exchange coil to within the inner heat exchange coil, through the inner heat exchange coil, and into the inner chamber.
U.S. Pat. No. 5,062,280, issued Nov. 5, 1991, to Martin, Sr. discloses an air conditioning apparatus with an enclosure which both houses a conditioning coil and serves as a plenum for transferring air to one or more conduits. In one aspect, vanes of the coil or coils are oriented to direct air toward openings in the plenum. An enclosure serves as a coil housing and as a plenum.
U.S. Pat. No. 6,276,443, issued Aug. 21, 2001, to Martin, Sr. discloses an air conditioning coil system having a first and a second outside tubing slab, a first and a second inside tubing slab, the inside tubing slabs positioned between the outside tubing slabs, a top of the first outside tubing slab contacting a top of the first inside tubing slab, a top of the second outside tubing slab contacting a top of the second inside tubing slab, and a bottom of the first inside tubing slab contacting a bottom of the second inside tubing slab, each tubing slab having a plurality of spaced-apart heat exchange fins, each outside tubing slab having a plurality of spaced-apart tubing rows extending through the plurality of heat exchange fins of the corresponding outside tubing slab, and each inside tubing slab having at least one tubing row extending through the plurality of heat exchange fins of the corresponding inside tubing slab. The air conditioning coil system wherein the at least one tubing row of each inside tubing slab is one row less than the number of tubing rows of the plurality of spaced-apart tubing rows in one of the outside tubing slabs.
U.S. Pat. No. 6,664,431, issued Sep. 9, 1997, to Martin, Sr. discloses a drain pan system for receiving water condensed on and flowing from an air conditioning coil, including a pan with a pan member for receiving and holding water from the coil, and the pan member having a side lip for connecting to an adjacent pan, the adjacent pan adjacent the coil and disposed at an angle to the pan member. In one aspect, the drain pan is used with the coil which is generally in a V-shape when viewed from an end thereof. In one aspect, the system includes a lateral pan or pans sealingly connectible to the adjacent pan and to which the pan member is sealingly secured.
U.S. Pat. No. 5,284,027, issued Feb. 8, 1994, to Martin, Sr. discloses a drain pan with an opening or openings through which air flows to a coil and a coil which, in one embodiment, has a cover plate so air flowing through a drain pan flows between vanes of a coil rather than out from an opening at an end of the coil; such a pan in combination with such a coil; and a system with such a coil-pan combination which uses a single pan for multiple orientations of the coil-pan combination in both horizontal flow, up-flow, and down-flow systems.
U.S. Pat. No. 4,665,806, issued Sep. 12, 1985, to Martin, Sr. discloses an air distributor for mounting in a duct outlet in an air conditioning heating and ventilation system is provided to direct the flow of air within the conditioned space. A frame is mounted within the conditioned space and in fluid communication with the outlet of the duct. The frame has an opening therethrough. A deflection member is movably mounted to the frame from an open position wherein the air can flow into the conditioned space to a closed position where essentially no air flows into the conditioned space. The deflection member is selectively adjustable in intermediate positions between the open and closed positions. A diverter is provided with the deflection member and is accessible for adjustment from the conditioned space to selectively direct the air flow between the frame and deflection member into the conditioned space in a two way, three way and four way pattern.
U.S. Patent Publication No. 20050047974, published Mar. 3, 2005, to Martin, Sr., discloses a plenum system with air flow structure for enclosing a coil of an air treatment system. The air flow structure in certain aspects has a container with at least two openings for air flow therethrough, the container having an interior surface, and the interior surface having ultraviolet-resistant material thereon; and methods for using such an air flow structure.
U.S. Pat. No. 5,927,096, entitled “Air conditioning System and Method,” issued to Piccione, which is incorporated herein by reference, discloses an air conditioning apparatus and method which provides for a bi-flow coil housing having air flow connection ends that are substantially identical. These coil housing features allow the coil housing to have either a right-hand or left-hand coil configuration to thereby allow installation flexibility so that the coil refrigerant and drain connections are readily available. In furtherance of this feature, a transition member and a plenum have substantially similar or identical ends for connection to the coil housing and may be connected to either end of the coil housing. Because there is only one end of the transition member that will vary in size thereby greatly reducing the number of different possible combinations of connection sizes the transition member must accord, a plurality of prefabricated transition members are preferably stored in the warehouse based on the type of heater. The use of a prefabricated transition member specifically designed for the specific type of heater and coil housing provides a quicker and precision fit there between.
The solutions to the above described and/or related problems have been long sought without success. Consequently, there remains a need to provide equipment and methods for coils and mounting methods. Those of skill in the art will appreciate the present invention, which addresses the above problems and other significant problems uncovered by the inventor that are discussed hereinafter.